Telegraphy.



L. M. POTTS.

TELEGRAPHY. APPLICATION man m96, 1912.

labented Apr. 13, 39M.

.im la l@ l, Ljillf/IL M M JL'IE? FITS, ill? TBLTJIMGRE, MARYLZNB,ASSGNQR '.lO AUSTIN MOLANAHAN, 0l? BALTIMB/E, MARYMNI).

Specification of Lettera Patent.

.application flied August 6, 191%. terial lio. 7135568.

more fully appear, .my said invention isY really not limited to suchrestricted use.

lt is usual in commercial telegraph practifs ot today to have. a loopedWire 'from 'entrai oiiice to a subscriber. 'W' invention .contemplatesthe utilization .iis looped wire to torm legs of two sim lines.,A oneused by the subscriber for sending to central, and the other, by centralto send to the subscriber. Such a system, therefore, has the'capacity oia one Wire duplex ,.lin'e Without its disadvantagcs'since, iu my systemartificial lines and balanced line relays not necessary. .Moreover7 inthe present arrangement, it is not necessary to provide syncliironizingapparatus at both stations. Yllhis apparatus may, for example.,

be at the centrall oiiice alone, and the subscriber provided 'with lineunit which may be drivenby a simple electric motor with.

out any synchronizing attachment.'

tlier advantages of this invention will more readily appear from thefollowing del scription in `which reference will be had to accompanyingdrawing which is a diagram illustrating; one embodiment ot my saidinvention. l

Referring to the accompanying drawing, y,tiene partyon theelett oliD thevertical broken lin l .in te the apparatus and connections at asubscribes station, for example, While those parts on the right ci saidline indi the apparatus at a central ollice.

in the case shown the apparatus at the scrbers station includes7 vamong;other pa. ts7 a line unit comprising `a trfuismittinp,r sunflowerconsisting; of a segmented ring or commutator 1 and a collector ring 2;a receiving sunower consisting of a segmented ringr or commutator 3 anda collector ring -l brushes 5, 6, 7 and 8 for the respectivecoininutators and collector rings and a direct current motor 9 drivingall said. brushes.

lilac brushes 5 and 'fare in permanent electrical connectionrespectively with brushes 6 and 8 as indicated. Eight segments of thecolninutator l are electrically connected respectively with eightmovable Contact springs 10, each of which isadapted to `more between apair of stationary contacts 11 and 12, and each pair of these stationarycontacts are alternately connected to two conductors 13 and 14, leadingfrom a source of current consisting in the present case` of two directcurrent dynamos 15 and 1G. The positive brush of dynamo 15 is connectedto conductor 13, and the negative brush of dynamo 1G is connected toconductor 14, while the other brushes of these two dynamos connect toearth as shown. ln this Way conductor` 13 receives a continuouspositive. current While conductor 1l receives a continuous negativecurrent. The extra segments of commutator l, not connected to contacts10, are Aalternately connected as shown to conductors 13 and 14.

All the contacts 10 normally engage stationary contacts l2, and sincealternate contacts 12 are connected to the same one of the Vwires 13,lll, an alternating,- current will be normally delivered to line as thebrush sweeps over commutator 1. The manner of operating kcontacts 10 totransmit the signais constitutes no part of my present invention, soneed not here be described in detail. Suiiice it to say that thesecontacts' may be operated in any suitable Way, either manually as Jiroma keyboard or automatic-` ally. ln U. S. Patent No. 1105920 grantedAugusta, 1914, ll have described both mauual and automatic means whichmay be ernploved' for operating these contacts.

Eight successive segments of the receiving commutator f3, in the caseshown, occupying corresponding angular positions to the eighttransmitting segments above referred to and 4are electrically connectedrespectively to al coil terminal ot each of eight selecting relays 17,the other coil terminals of which relays all connect toa commonconductor' 18 connected to earth as shown. The entra segments ofcommutator 3., not connected-to relays 17 i are all connected:to-conductor 18. '.lliese extra segments may be utilized for variouspurposes which it is not necessary here to enlarge upon., ln thelpresent case it is i sullicient to simply show these segments connectedto a conductor 18. l.

lfbe receiving'relays 17 may be made to lllt) flower above referred toindicate or record the received signals in any desired way, thisoperation forming no parto my present invention. In my British patent,above referred to, such receiving relays are employed for the operationof a page printer.

Extending respectively from the collector rings 2 and 4 are two linewires 19 and 2O which lead from the subscribers station to'y and thereconnect ree the central station, spectively two collector rings 21 and22 of the central line unit. This latter line unit comprises,'in thecase shown, a transmitting sunliower consisting of aV segmented ring orcommunicator 23, collector ring 21, and brushes 24 and 25, permanentlyelectrically connected as indicated; a receiving sunflower comprisingcommutator 26, collector ring 22, and electrically connected brushes 27and 28; a synchronizing commutator 29, collector ring 30, andelectrically connected brushes 31 and 32, and a synchronously drivendirect current motor 33 which drives all the brushes 24, 25, 27, 28, 31and 32 of the central line unit.

The transmitting apparatus at the central station comprises in additionto the sun a series of movable transmitting contacts 34 and stationarycontacts 35, 36, electrically connected to conductors v37 and 3S, and tothe transmitting comnuitator as described with reference to thetransmitting contacts 10, 11 and 12, and conductors 13, 14 at thesubscribers station. TL: conductors 37, 38 at the central station are inelectrical connection respectively with a positive and'ncgative terminalot' two direct current dynamos 39, 40 at the central sta-tion. The otherterminals of these dynamos are connected to earth as described withrelation to the dynamos at the subscribers station. I

At the central station the receiving apparatus comprises, as in the caseof the subscribers apparatus, eight selecting vrelays 41, which 4areconnected 'to the receiving commutator 26 as described with relation tothe relays 17 at the subscribers station, and the coils of all theserelays 41l are connected to a common. conductor 42, which connects tothe odd segments of commutator 26 and to earth as described with relation to conductor 18, except in the case of the conductor 42 there isincluded in its circuit between the last of the relays'41 and earth, thecoils of a synchronizing relay 43. A lternatc segments of thesynchronizing connnutator 29 are .connected respectively to the tonguecontacts 44 and 45 of this relay, while the tongue ot said relay ispermanently connected to a conductor 46 which leads to one of thebrushes ot' motor 33, the latter motor receiving its driving currentfrom D. C. mains 47 and 48.

Tapped at one side to wire 46 and at the of the commutator other to D.C. mains 47, is the synchronizing resistance 49 .which is utilized toregulate the speed of motor 33 as hereinafter de scribed.

Thdmeans here shown for regulating the motor 33 to sy chronism with themotor 9. said meansnincliiding relay 43, the synchron izing sunflowerand resistance 49. and electrical connections of these parts, except asto the connection of relay 43 to the conn mutator 26, is substantiallythe same shown and described in U. S. Patent No. 726,750,

`granted to me April 28, 1903, and while not herein claimed will bebriefly described in order that the parts shown may be more readilyunderstood.

The tongue of relay 43 is kept in constant vibration between contacts 44and 45 by an alternating current received from dyna mos 15, 16 throughconductors 13, 14 contacts 10, commutator 1, collect-or ring 2, line19,. collector ring 22, receiving commutator 26, relays 41 and conductor42, assuming that both motors 9 and 33 are operating. Now, if the tongueof relay 43 is against either of its contacts 44, 45. while brush 31 ispassing over any ot' the segments 29 connected to the relay contact withwhich the tongue is at that time engaging` it will be seen that theresistance 4f) will be short eircuited; while if the said relay tongueis engaging either oi said contacts at the same time that the brush 31is passing over any of the segments of commutator 29 connected to theopposite relay contact, that is, the one \\l1icl1the tongue is,not at'that time engaging, the resistance 49 will be in series with the ture ofmotor 33. In one case the motor will receive much greater current thanin the other. Consider any case in which the vibrations of the relaytongue and rotation of the brush have some relation between the abovetwo. If any relation between the irsttwo mentioned is continuouslymaintained, it will be readily seen that at rapidly recurring intervalsthe resistance 49 will be in circuit and out of circuit with the motor33. Depending upon the relation between the vibration of the relaytongue and the rotation of said brush, the intervals during which thisresistance is in circuit and out of circuit with the motor armature willvary in length, and in addition to the regular current flowing throilghthe motor armature, there will be a pulsating current flowing throughthe same, and the strength of these impulses Will depend upon therelation existing between the vibrations of the tongue of the relay 43and the rotation of the brush 31, consequently, while the relay tongueis vibrating 1n unison with the rotation of said brush, there can be,various amounts of current flowing through the armature of the motor,ldepending upon the arma-- iaeaeia relation of' the tongue of relay 43,to the l ush 3l which is hereafter spoken of as e p ase difference. ltthe rate of vibraion-ot the relay tongue increases, the phase ionbetween the 'vibration oit said relay ue and the natation et the brusharm change, but in such a manner as to Ven the impulses tlowingthronghthe nature, and, consequently, the 'le motor will be increased, but thisspeed corresponds to the ation oi the 'relay tongue. li the armature otthe motor attempts to go than ty e vibration of the relay tongue, theimpul weakened and the speed is stili lrept normal. Consequently thespeed oi' the motor follows any changes in the vibrations ot the relaytongue and any tendency 'for the motor to change speed., as, forinstance, a change i" the volta,J tely compensated by a slight shift inthe phase ditte-rence above mentioned,

frequency ot the alternations ot the current deiivered to relay isdeter* mined by l speed-ot motor 9, willbe n motor at tlie subscribersstu- Uli means Jor regulating its speed to synchronism. While thesemotors Vin practice oi course run at the same speed, motor 33 isactually designed to run at a higher speed than motor 9. `r`or example,motor 33 has `been designed to run at 2200, and .noter 9 at 1500revolutions per circuit. decrease in the speed of motor 33 by itsregulating resistance.

Signals may be transmitted trom the sub-- :im scriber to central byoperating the contacts l@ so as to bring these contacts in variouscombinations into engagement withy contacts il, ereby sending te lineimpulses of oppositie polarity vfrom normal'. rlihe receivcoils operateall lrelays so as tolsend their tongues against their. back stops.rlheretere, when a given combination of contacts. it are operated totransmit to line a correspondmg combination oit impulses oi" oppositepolarity A.trom normal' these impulses 'will be received bycorresponding relays 41,3' which will thereby be causedr to send theirtongues against ltheir torward contactsand thus operate the desiredreceiving apparatus. dn a similar way sig-- nuls are tri nsmitted to therelays l? ot the subscriber from the transmitting contacts at M thecentral station.'

ant that the sunflower brushes at fthe two stations be driven accuratelyin synchronism.

lt will be observed, however', that while s through the armature arevthe power circuit, immesets the pace and, need not have any' minute on a110 volt This is necessary to allow tor thel ing.. relays il central areso wound that tne normal-impulses passing through their lt will,therefore, be seen that itis importthereare? two sources of signalingcurrent,`

the transmitting sunflower at one station only, in the case shown, thesubscribers station.

" l do not, however, wish to be understood as limiting my invention toany one specific way of synchronizing the motor 33, since this may bedone inl other ways than that shown.

'lihe reversed signal impulses do not intertere with the. synchronism solong as their number is less than fifty percent of 'the total number ofimpulses received by relay 43. As long as this proportion is mainntained the synchronism will be amply maiutained during the reversals bythe inertia, of the moving parts.

The extra'. segments in the commutatore l, 3, 23 and 26, hereinafterreferred to, may be used'for '/various pur oses which it is notnecessary to describe. n the drawing they are simply shown connected toprevent a gap in the current transmitted to line. Also, means maybeprovided for automatically causing the brushes of the receivingcommutators to adjust themselves to angular positions corresponding totheir respective transmitting brushes so as to arrive simultaneously oncorresponding segments with the latter brushes. This, however, while animportant matter in the practical operation of the system is not claimedas a part of the present invention so needl not be here described. @neway ot accomplishing this is shown and described in U. S. Patent No.713,497, granted Novemher 11, 1902, in the Rowland System.

Various modiications of the specific em- I but- What l claim is: i l. Anelectric telegraph, comprising two separate transmission linesconnecting two stations, a ,separate source of vsignaling curn rentforeach of said lines, transinittinon and receiving apparatus for each ofsaid ines the transmitting apparatus of each ot sai lines comprisingmechanism to time the transmission of impulses to said lines from saidsources, and means at one of said stations governing the speed ofoperation of the impulse .timing apparatus at both stations.

2. A11 electric telegraph, comprising two separate transmission linesconnecting two it two stations,

2G Stations from which 30 'said stations stations, a separate source ofsignaling current for each of said lines, a transmitting and a receivingsunflower for each of said lines, means common to both the-transmit- 5ting and receiving sunflowers at one station to drive the same, andcommon driving means for the transmitting and receiving sunflowers atthe other station on said lines, the driving means for the sunflowers atone station settine' the ace and 'tiininv the duraing the same.

4f. An electric telegraph comprising transmitting and receivingTsunflowers at each of two stations, two separate lines connectingrespectively the transmitting sunflowers at with the receivingsunflowers at the distant station, an independent source of signaling.current at each of said stations from which impulses are transmitted tosaid lines respectively-through the transmitting assenze an independentsource of signaling current at each of which impulses 4are transmittedto said lines respectively through the transmitting sunflowers connectedthereto, an electric motor at one of said stations driving both thetransmitting and receiving sunflowers at that station, an electric motorat the other of said stations driving both said sunflowers at thatstation, and means at the latter station governed by the signalingcurrent from the distant station to regulate the speed of the secondnamed motor to synchronism with that of the rst named motor.

In testimony whereof I allix my signature in presence of two witnesses.

LoUIs M. rorrs.

LEE,

Witnesses:

COLUMBUS V. D. ROBINSON.

driving the saine,

